MathDB
BXMY is cyclic

Source: All Russian 2014 Grade 10 Day 2 P2

May 3, 2014
geometrypower of a pointgeometry proposed

Problem Statement

Let MM be the midpoint of the side ACAC of ABC \triangle ABC. Let PAMP\in AM and QCMQ\in CM be such that PQ=AC2PQ=\frac{AC}{2}. Let (ABQ)(ABQ) intersect with BCBC at XBX\not= B and (BCP)(BCP) intersect with BABA at YBY\not= B. Prove that the quadrilateral BXMYBXMY is cyclic.
F. Ivlev, F. Nilov